Blower doesn't work - http://www.hvacmechanic.com/ Forums

Original message

MyHvac31

148.150.30.3

"Blower doesn't work" , posted Wed 30 Apr 14:19

After a recent power outage in our neighborhood the main blower in my furnace doesn't work. There is a Honeywell sail switch mounted in the return air duct just before the Honewell Elec Air cleaner. I think they are connected in the same circuit because their is no power to either of them. This is a highboy type furnace (Armstrong Ultra80) sold through MagicChef?

Any suggestions would be greatly appreciated.

Replies:

yuri

205.200.193.53

"Re(1):Blower doesn't work" , posted Wed 30 Apr 19:42

You may have had a power surge when it came back on. It may have damaged the circuit board. If the burner comes on with no blower then it is not a blown fuse on the circuit board. If nothing works then check the board for a 3 or 5 amp auto type fuse. The sail switch turns on power to the EAC when the fan moves air past it. No fan, no air movement.

Yuri

MyHvac31

148.150.30.3

"Re(2):Blower doesn't work" , posted Thu 1 May 13:20

The burner and inducer motor turn on but they shut off after it gets too hot. Based on this information and what you said, it sounds like a bad circuit board, or logic board, or electronic control module (ECM).

This circuit board has a cover over it but the terminal connections are exposed. Does the cover come off easily?

yuri

207.161.220.115

"Re(3):Blower doesn't work" , posted Thu 1 May 15:34

Don't know. Not much you can do with it anyway. A few electronics guys have replaced the relay but it is soldered on and you have to be one of them.

Yuri

MyHvac31

148.150.30.3

"Re(4):Blower doesn't work" , posted Fri 2 May 10:24

Yesterday I had an HVAC service guy come to my house to diagnose and fix the problem. His diagnosis is the blower motor is shot. To make this diagnosis he turned on heat command to the furnace to observe the behavior: the inducer blower turned on, the burner ignited, we could see the limit switch rotating as the heat built up until a certain limit was reached (command???) then voltage energized a relay (could hear it click and measure voltage). So voltage was being applied to the main blower motor but the motor wasn't turning on. We tested to see if the other motor speeds would work by bypassing voltage to the relay . The motor still did not work. The service guy will come back today with a new motor.